blk-mq: fix potential oops on out-of-memory in __blk_mq_alloc_rq_maps()

__blk_mq_alloc_rq_maps() can be invoked multiple times, if we scale
back the queue depth if we are low on memory. So don't clear
set->tags when we fail, this is handled directly in
the parent function, blk_mq_alloc_tag_set().

Reported-by: Robert Elliott  <Elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index a7d70a1..e83d306 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1959,7 +1959,6 @@ out_unwind:
        while (--i >= 0)
                blk_mq_free_rq_map(set, set->tags[i], i);
 
-       set->tags = NULL;
        return -ENOMEM;
 }